Author Topic: Reflexing a finished bow? Edited for quote accuracy  (Read 4779 times)

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icu812

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Reflexing a finished bow? Edited for quote accuracy
« on: February 26, 2015, 11:27:02 am »
Just read something in the TBB vol 2 in the section titled "Bending Wood" that piqued my curiousity:

"I once had a yew stave that had a natural deflex of about two inches. Since any yew is available in my area, I made a b ow from the wood. This was an English style bow that worked slightly in the handle. It followed the string about three inches. I was frustrated because the bow was a mediocre performer, and so decided to steam a reflex into the handle and see what happened. I steamed the bow and clamped it into a press so the limb tips were in a straight line with the handle. Ultimately, the string follow fell to about two inches. The bow gained about three pounds in draw weight. Performance improved significantly. I was a happy camper."

I was just curious if anyone else has every tried adding reflex/recurve to the handle/tips of a finished and shot-in bow? If so, what were your experiences? Do you guys think it would broaden the chances of failure if a straight limb bow was reflexed after it's already been subjected to the forces of compression?
« Last Edit: February 26, 2015, 01:32:30 pm by icu812 »

Offline adb

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Re: Reflexing a finished bow?
« Reply #1 on: February 26, 2015, 11:30:02 am »
I had a short yew self flatbow that took 2" of set and I recurved the tips. The bow was transformed.

Offline Springbuck

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Re: Reflexing a finished bow?
« Reply #2 on: February 26, 2015, 12:03:45 pm »
I do it on purpose now,  but I used to do this by accident of out of necessity all the time.  Heat treating has changed things a lot as far as what I do and how I do it, along with the principle of never pulling a bow during tiller to more than its intended draw weight.  BUT....

Most of my early selfbow efforts took more set than I wanted, but long before Marc wrote about it in TBB, guys were talking about heat treating, so I started doing it.  I would start a bow, get it almost tillered, and see it start taking set, maybe 1-1/2 to 2". Then I would routinely either flip 6-8" of the tips forward 2" or so on a shorter to medium length bow (nothing like a real recurve, no string touching at brace) OR cook reflex into the first 2-3" off the handle , or into the handle, so the whole thing was reflexed.  In either case I would then toast the whole limb straighter.

Heat treating reflex back into a badly set bow doesn't seem to restore it to me, and Marc says it doesn't, but it seems to at least freeze it in it's tracks.  The first third of a limb or so often gets overworked, but that area right next to the handle up into the fades doesn't seem to, and can be set forward with heat. A little of that goes a long way, then I set the longer bows limbs straight on a board and the limb itself would take less set or stop settling at the least. 

On the flipped tips,  almost no bow design I was making bends much at all in those last few inches, so flipping 6" foreward didn't cause more set, didn't cost me stability , or require much tip weight.  No downside except the risk of screwing it up, or maybe making the tip lean to one side if the cross section wasn't nicely symmetrical laterally.  You gain string tension at brace and improve the F/D curve.

I still do this, but now I plan it rather than react to problems as I saw them.

Offline PatM

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Re: Reflexing a finished bow?
« Reply #3 on: February 26, 2015, 12:20:53 pm »
Just read something in the TBB vol 2 in the section titled "Bending Wood" that piqued my curiousity. Jim Hamm said something along the lines of, and I can't quote as I don't have the book in front of me at the moment:

He took a finished yew flatbow with straight limbs that was a very poor performer, with some 3+ inches of string follow and very poor cast, and later reflexed it 1-1/2 inches in the handle as an experiment. He said, to sum it up, something like - it brought the bow to life, reducing the effective set, and giving it 5+ fps speed increase and much smoother shooting characteristics due to its new reflex-deflex profile.

You don't remember the quote or the author very well. ; 

icu812

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Re: Reflexing a finished bow?
« Reply #4 on: February 26, 2015, 01:20:43 pm »
Springbuck: Interesting. I've left the tips stiff on the few bows I've made so far. Never thought if it that way I suppose. Can't hurt to put a little curve in something that never got worked in the first place. Thanks!

You get the idea Pat! It was the point of reflexing a finished bow I was after lol. I was skim reading last night while doing some laundry and ran across it. As folks can see from your snip-it, it's very vague and very poorly quoted  :-[. I'll edit it verbatim once I've got the book in front of me. (edited)
« Last Edit: February 26, 2015, 01:35:37 pm by icu812 »

Offline Pat B

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Re: Reflexing a finished bow?
« Reply #5 on: February 26, 2015, 01:31:04 pm »
He reflexed it in the handle...unstressed wood.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline PatM

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Re: Reflexing a finished bow? Edited for quote accuracy
« Reply #6 on: February 26, 2015, 01:38:42 pm »
He reflexed the handle but that puts more stress on the already stressed limbs which already had set.

  The whole concept of adding recurves or reflex to a shot in bow still seems to work. When wood has set it still seems to actually respond to being stressed even more, fresh wood and hysteresis theories notwithstanding.
 I still think that uniformly compacted belly wood with hard set acts like  harder wood the same way a forgewood cedar shaf does.

Offline bradsmith2010

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Re: Reflexing a finished bow? Edited for quote accuracy
« Reply #7 on: February 26, 2015, 02:20:38 pm »
yes I have done that will some success,, and some not so successful,, if the bow is disappointing you have nothing to loose,, :)

Offline Del the cat

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Re: Reflexing a finished bow? Edited for quote accuracy
« Reply #8 on: February 26, 2015, 02:25:40 pm »
Very old Yew ELB refubished successfully.
http://bowyersdiary.blogspot.co.uk/2014/04/refurb-progress.html
Del
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